I had planned to use today's entry to attack the age-vs-workload question using regression, but I ran into some technical problems with that. Maybe I'll get them fixed at some point. But they are not fixed right now and so today will be the first weekday since March 23rd that I have not posted some actual content.

Unfortunately, it won't be the last.

I teach in an intensive three-week summer school program for high school students. That started yesterday, so it'll have me pretty busy for the next few weeks. I will probably post two or three times per week until mid-July, and then we'll see what happens after that.

When I first started this, it felt like a struggle to come up with enough ideas to keep it going every day. Now I've got plenty of ideas but I'm struggling to find the time to write them up. That I find myself in the latter situation, which is far preferable, is largely attributable to the contributions made by you, the readers, in the comments and via email.

This entry was posted on Tuesday, June 20th, 2006 at 4:13 am and is filed under General.
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"So today will be the first weekday since March 23rd that I have not posted some actual content." You mean the Rothlesberger article doesn't qualify? You should do re-runs - like your famous hook-up article. Drag it out to - post it in 1/5 sections.

You deserve a break. I would rather you take days or even a week off, rather than get burned out after an intense period of posting, and stop altogether.

Maybe you could throw your offdays open for a "marketplace of ideas" on a football-related topic that you have not specifically researched.

To add some random football info to this day, in my late nights last week after the kids were in bed, I did some research using your database info, on home field advantage. I'll post it separately below. I found some (at least what my sick mind finds) interesting stuff.

I used the database info from 1986-2005 to look at home field advantage and distance between divisional opponents, and to see how distance mattered. The divisional games in this time period ranged in distance between teams from about 90 miles apart (Giants-Eagles) to about 2300 miles apart (49ers-Panthers in old NFC West).

When two "outdoor" divisional opponents played, here is how the home team did, sorted by distance between the cities.

There were very few dome vs. dome divisional games, all within 700 miles, and the home team only went 52-53 (49.5%).

I expected there to be some relationship between distance (whether due to travel, time zone changes, changing climates, among other things), but the extent of the effect on short distances is shocking to me. There has been basically no home field advantage for outdoor teams who are near each other in distance. In several of these series, like CHI-GB, CIN-PIT and NE-NYJ, the home teams won less than half the time. Also, after 500 miles, the advantage doesn't appear to continue to increase at even greater distances.

Interesting stuff, JKL. I think the next thing I would wonder is whether there are any selection biases involving team strengths because when you break it down by distances you would tend to get the same teams over and over again in each bucket.

Also, is there any logical explanation for why the distance would matter more for dome teams? It seems to me that you might want to back up a step and ask two simpler questions before combining them: Does travel distance matter? and Is the home field advantage different for dome teams?

Thinking out loud about JKL's numbers...if you ignore the within 300 miles games, there's very little difference in the HFA between outdoor-outdoor matchups and dome-outdoor matchups (59% vs. 57% if I've calculated correctly). So how would you explain the difference among close teams (assuming the difference is statistically significant, which I haven't bothered to check). On one hand, it makes sense that HFA would be smaller against a close team since there is likely to be a mix of fans of each team, mitigating any crowd noise effects. But why wouldn't this apply with dome teams? I'm thinking that several dome teams have been known to pump in canned noise via loudspeakers and maybe that has an effect, particuarly among closest divisional rivals.

Lou, re: your question in 6, it is all home games, played both in the dome and at the outdoor stadium. I didnt sort it specific to each site. But for example, the home team in the NO-SF series was 17-15, and in the ATL-SF series was 18-13. I am guessing that SF won a higher percentage at home than the other teams did, and it is due to them being the dominant team. However, the percentage is low not only because of sweeps, but because the Saints did have years where they won at SF then lost at home, almost as frequently as they split home and home.

Jim A, you are right about selection biases in post 8. I would hope this is minimized by two things: 1) over 20 years, teams will go through cycles and range in how good they are vs. their division opponents, and 2) by looking at multiple series, it cancels out some, with some more competitive than others.

However, that is not always the case, though it is true more often than not. SF was dominant for much of this period. STL/Arizona Cardinals were consistently much worse than their east coast division opponents. I do think that is what is going on at the outdoor v. outdoor games at the greatest distances. It's not that home field advantage decreased, its that the Cardinals were not very competitive, and make up several of those series.

I do not think this is a significant factor in the games within 300 miles. There are 11 total series here, involving 14 different teams. None of these series involved a significant home winning %. The highest was PHI-WAS, at 23-17 (57.5%).

On the dome teams at short distances, my unsupported speculation is that those games largely consist of the current NFC North (Min-GB, GB-Det, Chi-Det). The outdoor games can be played in much different, harsh conditions than the controlled environment of the dome, compared to series like SF-NO and SF-ATL, where distance is much greater but the outdoor games in SF are generally at temperatures near the dome conditions. Perhaps weather conditions are a bigger factor than raw distance in creating home field advantage?

I like the fact that you limited this study to divisional matchups since the home-and-home series limits the team strength selection bias. But it also makes me wonder whether HFA is any greater with evenly matched teams than with mismatched teams. That might shed some light on Arizona.

I also thought the NFC North games might be overrepresented, but it's still an interesting subgroup with two outdoor teams and two dome teams closely located in northern climates. Like you, I find HFA a fascinating subject and, strangely, not very well understood.

Does anybody know of any good web sites that deal with the subject of replacement players used in 1987. That was great! I remember the Bills beating the Giants 6-3. Lawrence Taylor was playing and blitzing on every play. Will Grant, who was previously retired, rejoined the team and was playing center. Marv said, "Come on, Will, you were called for holding 8 times." Grant replied, "That's not too bad, considering I was holding him on every play!"
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I give the league a lot of credit for going ahead with the games. I wish I had paid more attention at the time, as it was historical.